This invention relates generally to a sheet feeding apparatus employed in an electrophotographic printing machine, and more particularly concerns an apparatus for aligning a stack of sheets disposed within the sheet feeding apparatus.
Generally, an electrophotographic printing machine is provided with a suitable sheet tray for supporting a stack of sheets arranged to be advanced in seriatim therefrom. The sheet tray may include a friction pad or side guide adapted to engage the side edge portions of a stack of sheets disposed therein. In this way, the guide engages and aligns the side edge of the stack. By way of example, U.S. Pat. No. 3,408,064 issued to Johnson et al. in 1968, U.S. Pat. No. 1,964,498 issued to Brasseru in 1934, and U.S. Pat. No. 3,104,872 issued to Benson et al. in 1973 all discuss various types of devices arranged to engage the side edge portion of a stack of sheets for the alignment thereof.
However, a problem often encountered with such alignment devices is that the size of the sheets of support material varies. To this end, the guides are adapted to be moved to differing discrete positions corresponding to the nominal sizes of the sheets of support material employed in the electrophotographic printing machine. If non-standard size sheets of support material are employed, the guides will not generally contact the edge of the stack and the sheets therein may be misaligned.
Accordingly, it is a primary object of the present invention to improve the alignment device employed in sheet feeding apparatus by providing infinite adjustment therefore.